Semiconductor memory device and operating method thereof

ABSTRACT

A semiconductor memory device includes a memory region including a plurality of memory blocks, and suitable for outputting first and second read data from first and second memory blocks among the plurality of memory blocks based on first and second read control signals and a read address signal; a scheduler suitable for outputting a read scheduling signal based on the first and second read control signals; and an output driver suitable for outputting the first and second read data by a predetermined burst length alternately twice or more to a data pad based on a mode signal, wherein the first read data are outputted to the data pad according to a first burst sequence, and the second read data are outputted to the data pad according to a second burst sequence, based on the read scheduling signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(a) to KoreanPatent Application No. 10-2018-0040203, filed on Apr. 6, 2018, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND 1. Field

Exemplary embodiments of the present invention relate generally tosemiconductor memory devices, and more particularly, to a semiconductormemory device and an operating method thereof capable of more efficientand reliable reading of stored data.

2. Description of the Related Art

Semiconductor memory devices may employ a plurality of memory regionswhich may be grouped or organized in various ways. Generally, varioustechniques have been devised for improving the reading of data from theplurality of memory regions. However, constantly increasing demands forfaster, more reliable, high capacity semiconductor memory devices,requires further improvements in the reading of data from the variousmemory regions employed by a semiconductor memory device. For example,it is highly desirable that read control signals corresponding todifferent memory regions of the semiconductor memory device may beinputted gapless, and also that the semiconductor memory device mayoutput the read data gapless from the various memory regions.

SUMMARY

Various embodiments of the present invention are directed to asemiconductor memory device in which read burst sequence information foreach bank group is normally reflected when read data are alternatelyoutputted from different bank groups, and an operating method of thesemiconductor memory device.

In accordance with an embodiment of the present invention, asemiconductor memory device includes: a memory region including aplurality of memory blocks, and suitable for outputting first and secondread data from first and second memory blocks among the plurality ofmemory blocks based on first and second read control signals and a readaddress signal; a scheduler suitable for outputting a read schedulingsignal based on the first and second read control signals; and an outputdriver suitable for outputting the first and second read data by apredetermined burst length alternately twice or more to a data pad basedon a mode signal, wherein the first read data are outputted to the datapad according to a first burst sequence, and the second read data areoutputted to the data pad according to a second burst sequence, based onthe read scheduling signal.

In accordance with an embodiment of the present invention, an operatingmethod of a semiconductor memory device includes: outputting a burstsequence information signal corresponding to a first memory block and aburst sequence information signal corresponding to a second memory blockalternately twice as a read scheduling signal based on first and secondread control signals; outputting first read data having a first burstlength among first read data from the first memory block to a data padbased on the read scheduling signal for a first read period; outputtingsecond read data having a second burst length among second read datafrom the second memory block to the data pad based on the readscheduling signal for a second read period; outputting first read datahaving a third burst length among the first read data from the firstmemory block to the data pad based on the read scheduling signal for athird read period; and outputting second read data having a fourth burstlength among the second read data generated from the second memory blockto the data pad based on the read scheduling signal for a fourth readperiod.

In accordance with an embodiment of the present invention, asemiconductor memory device includes: a memory region including a firstmemory block and a second memory block, suitable for outputting firstread data from the first memory block and second read data from thesecond memory block, the first read data and the second read data have afirst length; a scheduler suitable for receiving a first burst sequencefor the first memory block and a second burst sequence for the secondmemory block, latching the first burst sequence and the second burstsequence, and alternatively generating the first burst sequence and thesecond burst sequence; and an output driver suitable for receiving thefirst read data and the second read data, and sequentially outputting aportion of the first read data, a portion of the second read data, aremaining portion of the first read data and a remaining portion of thesecond read data based on the alternatively generated first and secondburst sequences, wherein the portion of the first read data, the portionof the second read data, the remaining portion of the first read dataand the remaining portion of the second read data have a second lengththat is half of the first length.

These and other features and advantages of the present invention willbecome apparent to those skilled in the art of the invention from thefollowing detailed description in conjunction with the followingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a semiconductor memory device inaccordance with an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a scheduler shown in FIG. 1.

FIG. 3 is a block diagram illustrating an output control circuit shownin FIG. 2.

FIG. 4 is a block diagram illustrating a latch circuit shown in FIG. 2.

FIG. 5 is a block diagram illustrating an output circuit shown in FIG.2.

FIG. 6 is a timing diagram illustrating an operation of a semiconductormemory device shown in FIG. 1.

FIGS. 7 to 9 are tables for describing burst sequences according toembodiments.

DETAILED DESCRIPTION

Various embodiments of the present invention will be described below inmore detail with reference to the accompanying drawings. Theseembodiments are provided so that the disclosure of the invention isthorough and complete. All “embodiments” referred to in this disclosurerefer to embodiments of the inventive concept disclosed herein. However,it is noted that the embodiments presented are merely examples of theinvention and are not intended to limit the scope of the invention whichis defined in the appended claims. It will be understood that many otherembodiments and variations thereof may be envisioned by those skilled inthe art of the invention without departing from the scope of the claims.

Moreover, it is noted that the terminology used herein is for thepurpose of describing the embodiments only and is not intended to belimiting of the invention. As used herein, singular forms are intendedto include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including” are used inthis specification interchangeably to indicate the presence of anystated features and to not preclude the presence or addition of one ormore other non-stated features. As used herein, the term “and/or”indicates any and all combinations of one or more of the associatedlisted items. It is also noted that in this specification,“connected/coupled” refers to one component not only directlyconnected/coupled with another component but also indirectlyconnected/coupled another component through an intermediate component.

It will be understood that, although the terms “first”, “second”,“third”, and so on may be used herein to describe various elements,these elements are not limited by these terms. These terms are used todistinguish one element from another element. Thus, a first elementdescribed below could also be termed as a second or third elementwithout departing from the spirit and scope of the present invention.

The drawings are not necessarily to scale and, in some instances,proportions may have been exaggerated in order to clearly illustratevarious features of the described embodiments.

FIG. 1 is a block diagram illustrating a semiconductor memory device 100in accordance with an embodiment of the present invention.

Referring to FIG. 1, the semiconductor memory device 100 may include aclock buffer 110, a command buffer 120, a command decoder 130, ascheduler 140, a memory region 150, and an output driver 160.

The clock buffer 110 may generate an internal clock signal ICK based ona clock signal CK received from an external device (not shown). Theexternal device may be a host device employing the semiconductor memorydevice 100. The external device may be any suitable electronic device.

The command buffer 120 may generate internal command signals ICS andICA<0:M> based on command signals CS and CA<0:N> received form theexternal device. The internal command signals ICS and ICA<0:M> mayinclude an address signal representing a read burst sequence.Hereinafter, the address signal representing a read burst sequence amongthe internal command signals ICS and ICA<0:M> is referred to as a “burstsequence information signal ICA<K>”.

The command decoder 130 may generate a read address signal RD_ADDR andfirst and second read control signals RDT and IRDT based on the internalclock signal ICK, a mode signal 32BL and the internal command signalsICS and ICA<0:M>. Particularly, the command decoder 130 may activate thefirst read control signal RDT based on the mode signal 32BL and activatethe second read control signal IRDT after a predetermined time passes.The predetermined time may include a minimum time tCCD_S, which is to bedescribed below.

The mode signal 32BL may be set in advance in a mode register writecircuit (not illustrated). The mode signal 32BL may represent one burstlength operation among burst length operations that are supported in abank group mode. For example, the mode signal 32BL may represent a burstlength 32 operation among the burst length 32 operation and a burstlength 16 operation that are supported in the bank group mode.

The scheduler 140 may output a read scheduling signal B3LATSUMB based onthe first and second read control signals RDT and IRDT and the burstsequence information signal ICA<K>. For example, the scheduler 140 mayoutput the burst sequence information signal ICA<K> inputted previouslyand the burst sequence information signal ICA<K> inputted thereaftertwice alternately as the read scheduling signal B3LATSUMB.

The memory region 150 may include first to fourth memory blocks BG0 toBG3. Each of the first to fourth memory blocks BG0 to BG3 may includetwo or more banks. A bank may include a plurality of memory cellsorganized in rows and columns. Hereinafter, the first to fourth memoryblocks BG0 to BG3 are referred to as “first to fourth bank groups”.

The memory region 150 may output a read data RD_DATA based on the readaddress signal RD_ADDR and the first and second read control signals RDTand IRDT. For example, the memory region 150 may select any one of thefirst to fourth bank groups BG0 to BG3 based on the read address signalRD_ADDR, and output the 32-bit read data RD_DATA from the selected bankgroup based on the first and second read control signals RDT and IRDT.In other words, the memory region 150 may output 16-bit read data out ofthe 32-bit read data RD_DATA from the selected bank group based on thefirst read control signal RDT, and output remaining 16-bit read dataoutput the 32-bit read data RD_DATA from the selected bank group basedon the second read control signal IRDT. When the read address signalRD_ADDR is inputted twice consecutively, the bank group selected basedon the read address signal RD_ADDR inputted previously is referred to asa “first bank group”, and the bank group selected based on the readaddress signal RD_ADDR inputted thereafter is referred to as a “secondbank group”. The 32-bit read data RD_DATA outputted from the first bankgroup is referred to as “first bank read data”, the 16-bit read data ofthe first read data is referred to as “first part of the first bank readdata”, the remaining 16-bit read data of the first read data is referredto as “second part of the first bank read data”. The 32-bit read dataRD_DATA generated from the second bank group is referred to as “secondbank read data”, the 16-bit read data of the second read data isreferred to as “first part of the second bank read data”, and theremaining 16-bit read data of the second read data is referred to as“second part of the second bank read data”.

The output driver 160 may output the first part of the first bank readdata, second part of the first bank read data, first part of the secondbank read data and second part of the second bank read data alternatelyto a data pad DQ based on the read scheduling signal B3LATSUMB, the modesignal 32BL and a write clock signal WCK. For example, the output driver160 may output any one of the first part of the first bank read data andthe second part of the first bank read data as first output data to thedata pad DQ according to a first burst sequence included in the burstsequence information signal ICA<K> inputted previously for a first readperiod. The output driver 160 outputs any one of the first part of thesecond bank read data and the second part of the second bank read dataas second output data to the data pad DQ according to a second burstsequence included in the burst sequence information signal ICA<K>inputted thereafter for a second read period. The output driver 160outputs remaining read data, which is not selected among the first partof the first bank read data and the second part of the first bank readdata, as third output data to the data pad DQ according to the firstburst sequence for a third read period. The output driver 160 outputsremaining read data, which is not selected among the first part of thesecond bank read data and the second part of the second bank read data,as fourth output data to the data pad DQ according to the second burstsequence for a fourth read period.

The first and second burst sequences may be the same or different. Thefirst to fourth read periods may be continuous with each other gapless.Each of the first to fourth output data may have a burst lengthcorresponding to 16 bits.

FIG. 2 is a block diagram illustrating a scheduler in accordance with anembodiment of the present invention, for example, the scheduler 140shown in FIG. 1.

Referring to FIG. 2, the scheduler 140 may include an output controlcircuit 141, a latch circuit 143, and an output circuit 145.

The output control circuit 141 may generate a first output controlsignal RDTSUM<0> activated twice corresponding to the internal commandsignals ICS and ICA<0:M> inputted previously and a second output controlsignal RDTSUM<1> activated twice corresponding to the internal commandsignals ICS and ICA<0:M> inputted thereafter based on the first andsecond read control signals RDT and IRDT.

The latch circuit 143 may sequentially latch the burst sequenceinformation signal ICA<K> as first and second information signalsB3LAT<0:1> according to an input sequence based on first and second readcount signals RDT_CNT<0:1>. The first and second read count signalsRDT_CNT<0:1> may be generated from the output control circuit 141, whichwill be described in detail below.

The output circuit 145 may alternately select the first and secondinformation signals B3LAT<0:1> twice based on the first and secondoutput control signal RDTSUM<0:1> and output the selected informationsignal as the read scheduling signal B3LATSUMB.

FIG. 3 is a block diagram illustrating an output control circuit inaccordance with an embodiment of the present invention, for example, theoutput control circuit 141 shown in FIG. 2.

Referring to FIG. 3, the output control circuit 141 may include a firstcounting unit 141_1, a second counting unit 141_3, and a signalprocessing unit 141_5.

The first counting unit 141_1 may generate the first and second readcount signals RDT_CNT<0:1> based on the first read control signal RDT.For example, the first counting unit 141_1 may activate the first readcount signal RDT_CNT<0> when the first read control signal RDT isactivated firstly and activate the second read count signal RDT_CNT<1>when the first read control signal RDT is activated secondly.

The second counting unit 141_3 may generate third and fourth read countsignals IRDT_CNT<0:1> based on the second read control signal IRDT. Forexample, the second counting unit 141_3 may activate the third readcount signal IRDT_CNT<0> when the second read control signal IRDT isactivated firstly and activate the fourth read count signal IRDT_CNT<1>when the second read control signal IRDT is activated secondly.

The signal processing unit 141_5 may generate the first and secondoutput control signals RDTSUM<0:1> based on the first to fourth readcount signals RDT_CNT<0:1> and IRDT_CNT<0:1>. For example, the signalprocessing unit 141_5 may logically add (for example, perform an ORoperation) the first and third read count signals RDT_CNT<0> andIRDT_CNT<0> to generate the first output control signal RDTSUM<0>, andmay logically add (for example, perform the OR operation) the second andfourth read count signals RDT_CNT<1> and IRDT_CNT<1> to generate thesecond output control signal RDTSUM<1>.

FIG. 4 is a block diagram illustrating a latch circuit in accordancewith an embodiment of the present invention, for example, the latchcircuit 143 shown in FIG. 2.

Referring to FIG. 4, the latch circuit 143 may include a first latchunit 143_1, and a second latch unit 143_3.

The first latch unit 143_1 may latch the burst sequence informationsignal ICA<K> inputted previously as the first information signalB3LAT<0> based on the first read count signal RDT_CNT<0>.

The second latch unit 143_3 may latch the burst sequence informationsignal ICA<K> inputted thereafter as the second information signalB3LAT<1> based on the second read count signal RDT_CNT<1>.

FIG. 5 is a block diagram illustrating an output circuit in accordancewith an embodiment of the present invention, for example, the outputcircuit 145 shown in FIG. 2.

Referring to FIG. 5, the output circuit 145 may include a first outputunit 145_1, a second output unit 145_3, and a latch unit 145_5.

The first output unit 145_1 may output the first information signalB3LAT<0> as an output information signal B3LATSUM twice based on thefirst output control signal RDTSUM<0>.

The second output unit 145_3 may output the second information signalsB3LAT<1> as the output information signal B3LATSUM twice based on thesecond output control signal RDTSUM<1>.

The latch unit 145_5 may latch the output information signal B3LATSUM tooutput as the read scheduling signal B3LATSUMB.

Hereafter, an operation of the semiconductor memory device 100 havingthe aforementioned structure is described with reference to FIG. 6.

FIG. 6 is a timing diagram illustrating an operation of a semiconductormemory device in accordance with an embodiment of the present invention,for example, an operation of the semiconductor memory device 100 shownin FIG. 1.

Referring to FIG. 6, the clock buffer 110 of FIG. 1 may buffer the clocksignal CK to generate the internal clock signal ICK. The command buffer120 may buffer the command signals CS and CA<0:N> to generate theinternal command signals ICS and ICA<0:M>. The internal command signalsICS and ICA<0:M> and the burst sequence information signal ICA<K> whichcorrespond to the first bank group may be inputted, and subsequently theinternal command signals ICS and ICA<0:M> and the burst sequenceinformation signal ICA<K> which correspond to the second bank group maybe inputted gapless. The fact that the signals are inputted gaplessmeans that the signals are inputted at a minimum time tCCD_S interval toaccess different bank groups.

The command decoder 130 may generate the first read control signal RDTwhich is activated twice at the minimum time tCCD_S intervalcorresponding to the first and second bank groups based on the internalcommand signals ICS and ICA<0:M>. In addition, the command decoder 130may generate the second read control signal IRDT obtained by delayingthe first read control signal RDT by a predetermined time. Thepredetermined time may correspond to twice as much as the minimum timetCCD_S. The command decoder 130 may sequentially generate the readaddress signal RD_ADDR corresponding to each of the first and secondbank groups.

The memory region 150 may output the first read data from the first bankgroup and second read data from the second bank group based on the readaddress signal RD_ADDR, the first read control signal RDT and the secondread control signal IRDT.

The scheduler 140 may activate the first read count signal RDT_CNT<0>when the first read control signal RDT is activated firstly, activatethe second read count signal RDT_CNT<1> when the first read controlsignal RDT is activated secondly. Further, the scheduler 140 mayactivate the third read count signal IRDT_CNT<0> when the second readcontrol signal IRDT is activated firstly, and activate the fourth readcount signal IRDT_CNT<1> when the second read control signal IRDT isactivated secondly. Further, the scheduler 140 may logically add thefirst and third read count signals RDT_CNT<0> and IRDT_CNT<0> togenerate the first output control signal RDTSUM<0> that is activatedtwice at a time interval corresponding to twice as much as the minimumtime tCCD_S, and may logically add the second and fourth read countsignals RDT_CNT<1> and IRDT_CNT<1> to generate the second output controlsignal RDTSUM<1> that is activated twice at the time intervalcorresponding to twice as much as the minimum time tCCD_S.

The scheduler 140 may alternately select the burst sequence informationsignal ICA<K> (“0”) corresponding to the first bank group and the burstsequence information signal ICA<K> (“1”) corresponding to the secondbank group to output as the read scheduling signal B3LATSUMB based onthe first and second output control signal RDTSUM<0:1>.

The output driver 160 may alternately output the first part of the firstbank read data, the second part of the first bank read data, the firstpart of the second bank read data and the second part of the second bankread data having the same burst length to the data pad DQ based on theread scheduling signal B3LATSUMB, the mode signal 32BL and the writeclock signal WCK.

In this case, the first part of the first bank read data and the secondpart of the first bank read data may be outputted to the data pad DQaccording to the first burst sequence, and the first part of the secondbank read data and the second part of the second bank read data may beoutputted to the data pad DQ according to the second burst sequence. Thefirst and second burst sequences may be the same or different.

FIGS. 7 and 8 are tables for describing the first and second burstsequences according to embodiments.

As shown in FIG. 7, when the burst sequence information signal ICA<K>has a logic low level, i.e., ‘0’, the 32-bit read data may besequentially outputted according to a sequence defined by defaultvalues. When the burst sequence information signal ICA<K> has a logichigh level, i.e., ‘1’, the 32-bit read data may be sequentiallyoutputted according to a sequence changed in units of 8 bits as comparedwith the default values.

As shown in FIG. 8, when the burst sequence information signal ICA<K>has a logic low level, i.e., ‘0’, the 32-bit read data may besequentially outputted according to a sequence defined by defaultvalues. When the burst sequence information signal ICA<K> has a logichigh level, i.e., ‘I’, the 32-bit read data may be sequentiallyoutputted according to a sequence changed in units of 16 bits ascompared with the default values.

Although it is described as an example that a single burst sequenceinformation signal ICA<K> is used, the present invention is not limitedto this, and two burst sequence information signals ICA<K> and ICA<K′>may be used. When the two burst sequence information signals ICA<K> andICA<K′> are used, burst sequences corresponding to four cases may beapplied.

FIG. 9 is a table for describing first to fourth burst sequencescorresponding to first and second burst sequence information signalsICA<K> and ICA<K′>.

As shown in FIG. 9, when the first and second burst sequence informationsignals ICA<K> and ICA<K′> have logic levels of ‘00’, the 32-bit readdata may be sequentially outputted according to a sequence defined bydefault values. When the first and second burst sequence informationsignals ICA<K> and ICA<K′> have logic levels of ‘01’, the 32-bit readdata may be sequentially outputted according to a sequence changed inunits of 8 bits as compared with the default values. When the first andsecond burst sequence information signals ICA<K> and ICA<K′> have logiclevels of ‘10’, the 32-bit read data may be sequentially outputtedaccording to a sequence changed in units of 16 bits as compared with thedefault values. When the first and second burst sequence informationsignals ICA<K> and ICA<K′> have logic levels of ‘11’, the 32-bit readdata may be sequentially outputted according to a sequence changed inunits of 16 bits as compared that the first and second burst sequenceinformation signals ICA<K> and ICA<K′> have logic levels of ‘01’.

To sum up, an operating method of the semiconductor memory device 100may include outputting the burst sequence information signal ICA<K>corresponding to the first bank group and the burst sequence informationsignal ICA<K> corresponding to the second bank group alternately twiceas the read scheduling signal B3LATSUMB based on the first and secondread control signals RDT and IRDT, outputting the first part of thefirst bank read data generated from the first bank group to the data padDQ based on the read scheduling signal B3LATSUMB for the first readperiod, outputting the first part of the second bank read data generatedfrom the second bank group to the data pad DQ based on the readscheduling signal B3LATSUMB for the second read period, outputting thesecond part of the first bank read data generated from the first bankgroup to the data pad DQ based on the read scheduling signal B3LATSUMBfor the third read period, and outputting the second part of the secondbank read data generated from the second bank group to the data pad DQbased on the read scheduling signal B3LATSUMB for the fourth readperiod.

As is apparent from the above descriptions, in the semiconductor memorydevice and the operating method thereof, a read burst sequenceinformation signal allocated to each of a plurality of bank groups maybe accurately reflected when read data are alternately outputted fromdifferent bank groups.

As the read burst sequence information signal is normally reflected whenthe read data are alternately outputted from different memory blockseach including bank groups, operational reliability of the semiconductormemory device may be improved.

While the present invention has been described with respect to specificembodiments, the embodiments are not intended to be restrictive, butrather descriptive. Further, it is noted that the present invention maybe achieved in various ways through substitution, change, andmodification, by those skilled in the art without departing from thespirit and/or scope of the present invention as defined by the followingclaims.

What is claimed is:
 1. A semiconductor memory device, comprising: amemory region including a plurality of memory blocks, and suitable foroutputting first and second read data from first and second memoryblocks among the plurality of memory blocks based on first and secondread control signals and a read address signal; a scheduler suitable foroutputting a read scheduling signal based on the first and second readcontrol signals; and an output driver suitable for outputting the firstand second read data by a predetermined burst length alternately twiceor more to a data pad based on a mode signal, wherein the first readdata are outputted to the data pad according to a first burst sequence,and the second read data are outputted to the data pad according to asecond burst sequence, based on the read scheduling signal.
 2. Thesemiconductor memory device of claim 1, wherein the read schedulingsignal includes a burst sequence information signal inputted previouslyand a burst sequence information signal inputted thereafter alternatelytwice or more, and wherein the burst sequence information signalinputted previously includes an address signal representing the firstburst sequence, wherein the burst sequence information signal inputtedthereafter includes an address signal representing the second burstsequence.
 3. The semiconductor memory device of claim 1, wherein thescheduler includes: an output control circuit suitable for generating afirst output control signal that is activated twice or more and a secondoutput control signal that is activated twice or more, based on thefirst and second read control signals; a latch circuit suitable forsequentially latching the burst sequence information signal as first andsecond information signals according to an input sequence based on firstand second read count signals; and an output circuit suitable forselecting the first and second information signals alternately twice ormore based on the first and second output control signals and outputtingthe selected information signal as the read scheduling signal.
 4. Thesemiconductor memory device of claim 3, wherein the output controlcircuit includes: a first counting unit suitable for generating thefirst and second read count signals based on the first read controlsignal; a second counting unit suitable for generating third and fourthread count signals based on the second read control signal; and a signalprocessing unit suitable for generating the first and second outputcontrol signals based on the first to fourth read count signals.
 5. Thesemiconductor memory device of claim 3, wherein the latch circuitincludes: a first latch unit suitable for latching the burst sequenceinformation signal inputted previously as the first information signalbased on the first read count signal; and a second latch unit suitablefor latching the burst sequence information signal inputted thereafteras the second information signal based on the second read count signal.6. The semiconductor memory device of claim 3, wherein the outputcircuit includes: a first output unit suitable for outputting the firstinformation signal as an output information signal twice or more basedon the first output control signal; a second output unit suitable foroutputting the second information signal as the output informationsignal twice or more based on the second output control signal; and alatch unit suitable for latching the output information signal andoutputting the latched signal as the read scheduling signal.
 7. Thesemiconductor memory device of claim 1, further comprising: a commanddecoder suitable for generating the first and second read controlsignals based on a command signal, wherein the command decoder generatesthe first read control signal that corresponds to the command signal,and generates the second read control signal that toggles after apredetermined time passes from a toggling moment of the first readcontrol signal.
 8. The semiconductor memory device of claim 1, whereinthe memory region outputs each of the first and second read dataaccording to a third burst sequence, and the first to third burstsequences are the same as or different from each other.
 9. Thesemiconductor memory device of claim 1, wherein the output driveroutputs a portion of the first read data through the data pad for afirst read period, outputs a portion of the second read data through thedata pad for a second read period, outputs a remaining portion of thefirst read data through the data pad for a third read period, andoutputs a remaining portion of the second read data through the data padfor a fourth read period.
 10. The semiconductor memory device of claim9, wherein the first to fourth read periods are continuous with eachother gapless.
 11. The semiconductor memory device of claim 9, whereinthe portion of the first read data, the remaining portion of the firstread data, the portion of the second read data and the remaining portionof the second read data have the predetermined burst length.
 12. Anoperating method of a semiconductor memory device, comprising:outputting a burst sequence information signal corresponding to a firstmemory block and a burst sequence information signal corresponding to asecond memory block alternately twice as a read scheduling signal basedon first and second read control signals; outputting first read datahaving a first burst length among first read data from the first memoryblock to a data pad based on the read scheduling signal for a first readperiod; outputting second read data having a second burst length amongsecond read data from the second memory block to the data pad based onthe read scheduling signal for a second read period; outputting firstread data having a third burst length among the first read data from thefirst memory block to the data pad based on the read scheduling signalfor a third read period; and outputting second read data having a fourthburst length among the second read data generated from the second memoryblock to the data pad based on the read scheduling signal for a fourthread period.
 13. The operating method of claim 12, wherein the firstread data are outputted to the data pad according to a first burstsequence, and the second read data are outputted to the data padaccording to a second burst sequence which is equal to or different fromthe first burst sequence.
 14. The operating method of claim 12, whereinthe first to fourth burst lengths are the same as each other.
 15. Theoperating method of claim 12, wherein the first to fourth read periodsare continuous with each other gapless.
 16. The operating method ofclaim 12, wherein the outputting of the burst sequence informationsignal as the read scheduling signal includes: generating a first outputcontrol signal which is activated twice and a second output controlsignal which is activated twice at a predetermined time interval withthe first output control signal based on the first and second readcontrol signals; sequentially latching the burst sequence informationsignal as first and second information signals according to an inputsequence based on first and second read count signals; and selecting thefirst and second information signals alternately twice and outputtingthe selected information signal as the read scheduling signal based onthe first and second output control signals.
 17. A semiconductor memorydevice comprising: a memory region including a first memory block and asecond memory block, suitable for outputting first read data from thefirst memory block and second read data from the second memory block,the first read data and the second read data have a first length; ascheduler suitable for receiving a first burst sequence for the firstmemory block and a second burst sequence for the second memory block,latching the first burst sequence and the second burst sequence, andalternatively generating the first burst sequence and the second burstsequence; and an output driver suitable for receiving the first readdata and the second read data, and sequentially outputting a portion ofthe first read data, a portion of the second read data, a remainingportion of the first read data and a remaining portion of the secondread data based on the alternatively generated first and second burstsequences, wherein the portion of the first read data, the portion ofthe second read data, the remaining portion of the first read data andthe remaining portion of the second read data have a second length thatis half of the first length.